Cumulative ductility and fatigue life of Buckling-Restrained Braces under severe seismic loading conditions: An experimental study

Buckling-Restrained Braces (BRBs) are globally recognized for their ability to enhance the seismic performance of structures due to their stable cyclic behavior. However, concerns regarding their long-term stability under cumulative cyclic loads over a structure’s lifespan remain. This study addresses these concerns by subjecting six identical BRB specimens to quasi-static cyclic loading tests, with three tested under a standard incremental amplitude protocol and three under severe seismic deformation demands, all tested to failure under fatigue conditions. The results demonstrate that BRBs maintain stable hysteretic behavior up to peak ductilities of 13.9 and endure between 5 and 15 repetitions of seismic load protocols, with energy dissipation capacities far exceeding design basis earthquake demands. Detailed data on stiffness, load resistance, and overstrength factors in both tension and compression are provided, challenging the view of BRBs as sacrificial elements. Instead, the findings highlight their reliability and durability, suggesting they can provide robust seismic resistance throughout a structure’s service life. By advancing our understanding of BRBs’ long-term performance, this study underscores their critical role in enhancing structural resilience and emphasizes the need for further research to fully explore their potential in seismic design, ensuring more durable and resilient infrastructure.